Time-Dependent–3D Geomagnetic Cutoffs in an LFM Simulation with and without Electric Fields

Solar energetic particle cutoffs calculated using static magnetic field models are known to predict cutoff rigidities that are higher than those observed by spacecraft. Reasons for this might be incomplete models of the magnetosphere, lack of time dependence and/or electric fields. In this study we investigate the effects of time dependence and electric fields by calculating the cutoffs in a magnetohydrodynamic simulation using the Lyons-Fedder-Mobarry model and an MHD particle method Kress, 2005. The cutoffs were calculated both with and without electric fields using an MHD particle method.